AC Makes Floor Wet | Air Conditioner Leaking Water Inside House
Why is my AC leaking water inside? Complete guide to 6 common causes of AC water leaks on floors. Portland AC troubleshooting with solutions and repair costs.
Read Time
15 min
Service Area
Portland Metro
License
CCB #187834
Owner & Lead HVAC Technician
Finding water on your floor from your air conditioner is alarming and confusing. After all, AC systems are supposed to remove moisture from the air, not add water to your home. However, water leaks from AC units are surprisingly common, especially in Portland's humid climate with 165 rainy days per year.
The good news is that most AC water leaks have straightforward causes and solutions. This comprehensive guide covers the 6 most common reasons your AC might be leaking water inside your Portland home, along with DIY troubleshooting steps, professional repair costs, and prevention tips.
Whether you're dealing with a sudden flood or just noticing damp spots, understanding AC water leaks can help you respond quickly and prevent costly water damage or mold growth.
Normal vs. Problem Water
It's important to understand that AC systems are designed to produce water - about 5-10 gallons per day in Portland's humid climate. This water should drain safely outside through a condensate drain line. The problem occurs when this normal drainage system fails, causing water to leak inside instead.
6 Main Causes of AC Water on Floor
Clogged Condensate Drain Line
MediumMost common cause - algae, mold, and debris block the drain line, causing water backup.
Portland Factor: 165 rainy days create ideal conditions for algae and mold growth in drain lines
Symptoms:
Water dripping from indoor unit, gurgling sounds, reduced cooling
DIY Fix:
Clear with wet/dry vacuum, use drain cleaner
Cost: $75-$150 professional clearing
Frozen Evaporator Coil
HighLow refrigerant or restricted airflow causes coil to freeze, then thaw and flood drain pan.
Portland Factor: Spring/fall temperature swings and infrequent AC use increase freeze risk
Symptoms:
Water on floor when AC runs, reduced cooling, ice on copper lines
DIY Fix:
Turn off AC, allow coil to thaw (2-4 hours)
Cost: $200-$1,500 (refrigerant + repair)
Damaged Drain Pan
MediumRust, corrosion, or cracks in the drain pan cause leaks. Common in older systems.
Portland Factor: High humidity accelerates metal corrosion in Portland homes
Symptoms:
Water leaking from bottom of indoor unit, rust stains on ceiling/floor
DIY Fix:
None - requires professional replacement
Cost: $150-$300 for pan replacement
Disconnected Drain Line
HighDrain line comes loose from drain pan or gets disconnected during cleaning/service.
Portland Factor: Vibrations from infrequent AC use can loosen connections
Symptoms:
Sudden water leak after recent service or cleaning
DIY Fix:
Reconnect line and secure with clamps
Cost: $75-$125 if caught early
Dirty Air Filter
MediumClogged filter restricts airflow, causing coil freeze and water overflow.
Portland Factor: Cottonwood season (May-June) fills filters with pollen and debris
Symptoms:
Reduced airflow, higher energy bills, water leak when AC runs
DIY Fix:
Replace air filter immediately
Cost: $10-$30 for new filter
Low Refrigerant
HighRefrigerant leak causes coil to freeze and thaw, flooding the drain system.
Portland Factor: Older Portland homes may have undetected leaks from vibration
Symptoms:
Warm air from vents, hissing sounds, ice on lines
DIY Fix:
None - requires EPA-certified technician
Cost: $200-$1,500 (leak detection + repair)
Emergency Water Damage Prevention
Act Fast - Water Damage Happens Quickly
In Portland's humid climate, water damage and mold can begin within 24-48 hours. When you discover an AC water leak, immediate action is crucial to prevent costly damage to floors, ceilings, and structural components.
0-2 Hours
Water absorption begins, potential for staining
24 Hours
Mold spores begin germination
48+ Hours
Visible mold growth, structural damage possible
Immediate Steps
- 1.Turn off your AC system immediately to stop the leak
- 2.Mop up standing water with clean towels or rags
- 3.Place towels or buckets under the leaking area
- 4.Check for ceiling or wall damage above the leak
- 5.Run fans to dry the area and prevent mold
Call for Help
- •AC repair: Schedule technician within 24 hours
- •Water damage restoration: If significant damage
- •Insurance claim: Document damage with photos
- •Mold remediation: If water sits for 48+ hours
- •Emergency service: 503-698-5588 (24/7 available)
DIY Troubleshooting Steps
Step-by-Step AC Water Leak Diagnosis
- 1
Check Condensate Drain Line Outside
Locate the PVC drain pipe exiting your home from the AC unit. Check for clogs, kinks, or damage. Clear any visible debris. In Portland homes, this pipe often terminates in a floor drain or outside drain.
- 2
Inspect Overflow Pan
Look under your indoor AC unit for an auxiliary drain pan. Check if it's overflowing or damaged. This secondary pan catches water when the primary drain fails.
- 3
Look for Ice on Indoor Coil
Remove the front panel of your indoor unit and check the evaporator coil for ice formation. If you see ice, the coil is freezing due to airflow restriction or low refrigerant.
- 4
Check Air Filter
Inspect and replace the air filter if it's dirty or clogged. A dirty filter restricts airflow, causing the coil to freeze and overflow the drain pan.
- 5
Verify Drain Line Isn't Clogged
Pour water down the drain line or use a wet/dry vacuum to check for blockages. Listen for water flowing freely. Clear any clogs you can access safely.
- 6
When to Stop and Call Professional
If you can't identify the leak source, or if the leak persists after basic troubleshooting, call a professional HVAC technician to prevent water damage.
Professional Repair Options & Costs
Drain Line Clearing
$75-$150
- • Most common repair
- • Professional cleaning tools
- • Includes inspection
- • 30-60 minute service
Drain Pan Replacement
$150-$300
- • For rusted/cracked pans
- • Includes new pan and seals
- • 1-2 hour installation
- • Prevents future leaks
Coil Cleaning
$100-$400
- • Deep coil cleaning
- • Improves efficiency
- • 45-90 minute service
- • Annual maintenance item
Refrigerant Leak Repair
$200-$1,500
- • Leak detection and repair
- • Refrigerant recharge
- • 2-4 hour service
- • EPA certified required
Complete System Service
$150-$300
- • Full AC inspection
- • Multiple repairs
- • 2-3 hour service
- • Best value for complex issues
Emergency Service
+$100-$200
- • Same-day service
- • After-hours rates
- • Weekend surcharge
- • 24/7 availability
Portland Repair Costs
AC repair costs in Portland are competitive but vary by technician experience and parts quality. We recommend licensed technicians with manufacturer training for reliable repairs. Emergency services are available 24/7 for water damage situations.
Same-day service available • Financing options • Maintenance plans reduce future repair costs
Preventing Future AC Water Leaks
Regular Maintenance
- •Change air filters every 30-60 days
- •Annual professional AC tune-up
- •Clean condensate drain line quarterly
- •Inspect drain pan for corrosion
- •Check for proper drainage slope
System Upgrades
- •Install condensate pump for problem drains
- •UV light installation to prevent algae growth
- •High-efficiency AC with better drainage
- •Whole-home dehumidification system
- •Smart drain monitoring systems